In silver halide color photographic materials, particularly those for prints, recently it has been required to provided materials which have high sensitivity and which can be rapidly developed by rapid development processing. Further, it has become desirable to be able to provide a supply of prints having high quality without employing highly skilled labor. In order to respond to these requirements, it is important to maintain production stability of photographic light-sensitive materials, as well as to improve photographic properties thereof. More specifically to minimize differences in photographic properties between lots during the production of photographic light-sensitive materials and to keep the change in photographic properties as small as possible during storage of the photographic light-sensitive materials after the production for a long period of time are significant. Moreover, in photographic light-sensitive materials for prints it is particularly required that clear cyan, magenta and yellow colored dyes of less subsidiary absorption are formed to provide color photographic images of good color reproducibility.
Differences in photographic properties between lots during the production of photographic light-sensitive materials and changes in photographic properties, particularly, sensitivity and fog during storage of the photographic light-sensitive materials for a long period of time poses significant practical problems to the use of such materials. These problems lead to very severe defects under the recent conditions wherein high quality is especially required.
It is believed that changes in photographic properties largely depend on the properties of the sensitizing dye used, although it also depends partly on the inherent properties of the silver halide emulsion. Specifically, the changes depend on the change in the amount of sensitizing dyes adsorbed onto the silver halide grains when an emulsion for coating is stored for a long period of time at the production of the photographic light-sensitive materials or the change in the amount of sensitizing dyes adsorbed onto the silver halide grains due to desorption during the storage of the photographic light-sensitive material for a long period of time after its production.
It has been found that when a certain type of coupler (the compound represented by the general formula (I) described hereinafter) is present in a silver halide emulsion layer, the above described problems occur remarkably, not only in the silver halide emulsion layer containing the coupler, but also in other silver halide emulsion layers, in particular, in the red-sensitive emulsion layer.
Magenta couplers having a pyrazoloazole skeleton represented by the general formula (I) described hereinafter, particularly those as described in JP-A-59-171956 corresponding to U.S. Patent 4,540,654, JP-A-59-162548 corresponding to U.S. Patent 4,500,630, JP-A-60-33552 and JP-A-60-43659 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") are preferred from the standpoint of color reproduction because they exhibit less subsidiary absorption in the wavelength range around 430 nm, in comparison with the pyrazolone type magenta couplers generally employed in color photographic light-sensitive materials for prints. However, it has become apparent that these pyrazoloazole type magenta couplers cause the formation of severe fog and an increase in fog during their storage for a long time after production.
While several investigations on antifogging agents have been made in order to solve these problems, satisfactory results have not been obtained. It has been proposed in JP-A-61-245153 that an improvement has been made by hardening the layer with a chlorotriazine type hardening agent, and adjusting the pH of the photographic light-sensitive material to a range of from 5.0 to 6.0. In this reference, however, there is no disclosure on the prevention of fog in other layers, particularly in a red-sensitive emulsion layer, although there is the description relating to a green-sensitive emulsion layer.
Other attempts to reduce the difference in photographic properties between lots of the product and to improve preservability of the photographic light-sensitive material for a long period of time have been made, and improvements have been reported for methods involving the addition of water-soluble bromides (as described in JP-A-52-151026), the addition of iridium salts (as described in JP-A-54-23520), the addition of selective hardening agents (as described in JP-A-60-202436), the addition of super sensitizing agents (as described in JP-A-61-203447) and the improved addition method of spectral sensitizing dyes (as described in JP-A-58-7629).
In addition, in JP-A-60-225147 the addition of silver chlorobromide having (100) planes and (111) planes is proposed in order to improve spectral sensitivity and preservability with the lapse of time, and to reduce the difference between emulsion lots.
However, it is very difficult to reduce the difference between lots of the product and to improve the preservability for a long period of time to a satisfactory extent without causing adverse affects on the inherent photographic properties such as sensitivity, fog, contrast, image quality, etc. in case of applying these method individually or in combination. In particular, it can not be achieved to restrain the fog in a red-sensitivie emulsion layer.